The main thrust of this work is to develop biochemical methods for the early diagnosis of granulocytic leukemia and methods for inducing leukemic cells to develop some or all of their functional properties as a means of partially or completely restoring host defense mechanisms in leukemia patients. Work is first aimed at identifying the main molecular constituents and metabolic processes that distinguish normal mature granulocytes from their immature precursors and establishing which of the many steps involved in granulocyte maturation are regulated by factors present in body fluids and/or by cell-mediated factors. The results will be compared with those obtained from similar studies on leukemic cells at corresponding stages of maturity in order to determine the nature and potential reversibility of the arrested maturation steps. Biochemical analyses of molecular constituents are carried out on mature and immature granulocytes isolated from blood and bone marrow by velocity sedimentation and density centrifugation procedures developed in this laboratory. The effects of external cell regulators on granulocyte production and differentiation, as measured by changes in the synthesis of specific cellular components, are studied in a chemically defined culture system previously developed in this laboratory.